1. Field
Apparatuses and methods consistent with exemplary embodiments relate to an aperture adjusting apparatus for adjusting an aperture through which light transmits in a microelectrofluidic method.
2. Description of the Related Art
A technique of adjusting and controlling a transmissivity of light is widely used for an iris or a shutter in image acquisition devices or used to drive individual pixels in image display devices.
A variable iris generally used in existing optical systems mainly uses a method of manipulating several metal blades, wherein a mechanical motion, a frictional force, and the use of a moving mechanical element causes miniaturization to be limited.
Although a microelectromechanical system (MEMS) iris of an electrothermal or electrostatic scheme has been introduced, an aperture is non-circular, there is a gap between blades, and a maximum aperture ratio is problematically low as 1% or less of the whole device area.
Along with the development of optofluidic technology in which micro-optics and microfluidics are combined, a variable iris of which an aperture ratio is adjusted by modifying a polydimethylsiloxane (PDMS) membrane using air pressure has been proposed. In this case, a resolution of a variable iris is improved using a three-dimensional structure and a capillary force. Compared with an existing MEMS iris, this iris has a higher aperture ratio but has a limitation that a syringe pump is used for driving thereof.
In addition, an iris using a liquid lens for which a dielectric force is used as a driving principle has been recently proposed, and in this case, an aperture ratio is adjustable only with an electrical wiring on the bottom of the iris and not with an external driving pump.